.\" $OpenBSD: ASN1_STRING_length.3,v 1.20 2019/08/26 07:59:02 schwarze Exp $
.\" full merge up to: OpenSSL 4a56d2a3 Feb 25 16:49:27 2018 +0300
.\"
.\" This file is a derived work.
.\" The changes are covered by the following Copyright and license:
.\"
.\" Copyright (c) 2018, 2019 Ingo Schwarze <schwarze@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.\" The original file was written by Dr. Stephen Henson.
.\" Copyright (c) 2002, 2006, 2013, 2015, 2016, 2017 The OpenSSL Project.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in
.\"    the documentation and/or other materials provided with the
.\"    distribution.
.\"
.\" 3. All advertising materials mentioning features or use of this
.\"    software must display the following acknowledgment:
.\"    "This product includes software developed by the OpenSSL Project
.\"    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
.\"
.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
.\"    endorse or promote products derived from this software without
.\"    prior written permission. For written permission, please contact
.\"    openssl-core@openssl.org.
.\"
.\" 5. Products derived from this software may not be called "OpenSSL"
.\"    nor may "OpenSSL" appear in their names without prior written
.\"    permission of the OpenSSL Project.
.\"
.\" 6. Redistributions of any form whatsoever must retain the following
.\"    acknowledgment:
.\"    "This product includes software developed by the OpenSSL Project
.\"    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: August 26 2019 $
.Dt ASN1_STRING_LENGTH 3
.Os
.Sh NAME
.Nm ASN1_STRING_cmp ,
.Nm ASN1_OCTET_STRING_cmp ,
.Nm ASN1_STRING_data ,
.Nm ASN1_STRING_dup ,
.Nm ASN1_OCTET_STRING_dup ,
.Nm ASN1_STRING_get0_data ,
.Nm ASN1_STRING_length ,
.Nm ASN1_STRING_length_set ,
.Nm ASN1_STRING_set ,
.Nm ASN1_OCTET_STRING_set ,
.Nm ASN1_STRING_to_UTF8 ,
.Nm ASN1_STRING_type
.Nd ASN1_STRING utility functions
.Sh SYNOPSIS
.In openssl/asn1.h
.Ft int
.Fo ASN1_STRING_cmp
.Fa "const ASN1_STRING *a"
.Fa "const ASN1_STRING *b"
.Fc
.Ft int
.Fo ASN1_OCTET_STRING_cmp
.Fa "const ASN1_OCTET_STRING *a"
.Fa "const ASN1_OCTET_STRING *b"
.Fc
.Ft unsigned char *
.Fo ASN1_STRING_data
.Fa "ASN1_STRING *x"
.Fc
.Ft ASN1_STRING *
.Fo ASN1_STRING_dup
.Fa "const ASN1_STRING *a"
.Fc
.Ft ASN1_OCTET_STRING *
.Fo ASN1_OCTET_STRING_dup
.Fa "const ASN1_OCTET_STRING *a"
.Fc
.Ft const unsigned char *
.Fo ASN1_STRING_get0_data
.Fa "const ASN1_STRING *x"
.Fc
.Ft int
.Fo ASN1_STRING_length
.Fa "const ASN1_STRING *x"
.Fc
.Ft void
.Fo ASN1_STRING_length_set
.Fa "ASN1_STRING *x"
.Fa "int len"
.Fc
.Ft int
.Fo ASN1_STRING_set
.Fa "ASN1_STRING *str"
.Fa "const void *data"
.Fa "int len"
.Fc
.Ft int
.Fo ASN1_OCTET_STRING_set
.Fa "ASN1_OCTET_STRING *str"
.Fa "const unsigned char *data"
.Fa "int len"
.Fc
.Ft int
.Fo ASN1_STRING_to_UTF8
.Fa "unsigned char **out"
.Fa "const ASN1_STRING *in"
.Fc
.Ft int
.Fo ASN1_STRING_type
.Fa "const ASN1_STRING *x"
.Fc
.Sh DESCRIPTION
These functions manipulate
.Vt ASN1_STRING
structures.
.Pp
.Fn ASN1_STRING_cmp
and
.Fn ASN1_OCTET_STRING_cmp
compare the type, the length, and the content of
.Fa a
and
.Fa b .
.Pp
.Fn ASN1_STRING_data
is similar to
.Fn ASN1_STRING_get0_data
except that the returned value is not constant.
This function is deprecated.
Applications should use
.Fn ASN1_STRING_get0_data
instead.
.Pp
.Fn ASN1_STRING_dup
and
.Fn ASN1_OCTET_STRING_dup
copy
.Fa a .
.Pp
.Fn ASN1_STRING_get0_data
returns an internal pointer to the data of
.Fa x .
It should not be freed or modified in any way.
.Pp
.Fn ASN1_STRING_length
returns the length attribute of
.Fa x ,
measured in bytes.
.Pp
.Fn ASN1_STRING_length_set
sets the length attribute of
.Fa x
to
.Fa len .
It may put
.Fa x
into an inconsistent internal state.
.Pp
.Fn ASN1_STRING_set
and
.Fn ASN1_OCTET_STRING_set
set the length attribute of
.Fa str
to
.Fa len
and copy that number of bytes from
.Fa data
into
.Fa str .
If
.Fa len
is -1, then
.Fn strlen data
is used instead of
.Fa len .
If
.Fa data
is
.Dv NULL ,
the content of
.Fa str
remains uninitialized; that is not considered an error unless
.Fa len
is negative.
.Pp
.Fn ASN1_STRING_to_UTF8
converts the string
.Fa in
to UTF-8 format.
The converted data is copied into a newly allocated buffer
.Pf * Fa out .
The buffer
.Pf * Fa out
should be freed using
.Xr free 3 .
.Pp
.Fn ASN1_STRING_type
returns the type of
.Fa x .
.Pp
Almost all ASN.1 types are represented as
.Vt ASN1_STRING
structures.
Other types such as
.Vt ASN1_OCTET_STRING
are simply typedefed to
.Vt ASN1_STRING
and the functions call the
.Vt ASN1_STRING
equivalents.
.Vt ASN1_STRING
is also used for some CHOICE types which consist entirely of primitive
string types such as
.Vt DirectoryString
and
.Vt Time .
.Pp
These functions should
.Em not
be used to examine or modify
.Vt ASN1_INTEGER
or
.Vt ASN1_ENUMERATED
types: the relevant INTEGER or ENUMERATED utility functions should
be used instead.
.Pp
In general it cannot be assumed that the data returned by
.Fn ASN1_STRING_get0_data
and
.Fn ASN1_STRING_data
is NUL terminated, and it may contain embedded NUL characters.
The format of the data depends on the string type:
for example for an
.Vt IA5String
the data contains ASCII characters, for a
.Vt BMPString
two bytes per character in big endian format, and for a
.Vt UTF8String
UTF-8 characters.
.Pp
Similar care should be taken to ensure the data is in the correct format
when calling
.Fn ASN1_STRING_set .
.Sh RETURN VALUES
.Fn ASN1_STRING_cmp
and
.Fn ASN1_OCTET_STRING_cmp
return 0 if the type, the length, and the content of
.Fa a
and
.Fa b
agree, or a non-zero value otherwise.
In contrast to
.Xr strcmp 3 ,
the sign of the return value does not indicate lexicographical ordering.
.Pp
.Fn ASN1_STRING_data
and
.Fn ASN1_STRING_get0_data
return an internal pointer to the data of
.Fa x .
.Pp
.Fn ASN1_STRING_dup
and
.Fn ASN1_OCTET_STRING_dup
return a pointer to a newly allocated
.Vt ASN1_STRING
structure or
.Dv NULL
if an error occurred.
.Pp
.Fn ASN1_STRING_length
returns a number of bytes.
.Pp
.Fn ASN1_STRING_set
and
.Fn ASN1_OCTET_STRING_set
return 1 on success or 0 on failure.
.Pp
.Fn ASN1_STRING_to_UTF8
returns the number of bytes in the output buffer
.Pf * Fa out ,
or a negative number if an error occurred.
.Pp
.Fn ASN1_STRING_type
returns an integer constant, for example
.Dv V_ASN1_OCTET_STRING .
.Pp
In some cases of failure of
.Fn ASN1_STRING_dup ,
.Fn ASN1_STRING_set ,
and
.Fn ASN1_STRING_to_UTF8 ,
the reason can be determined with
.Xr ERR_get_error 3 .
.Sh SEE ALSO
.Xr ASN1_STRING_new 3
.Sh HISTORY
.Fn ASN1_STRING_cmp ,
.Fn ASN1_STRING_dup ,
.Fn ASN1_STRING_set ,
and
.Fn ASN1_OCTET_STRING_set
first appeared in SSLeay 0.6.5.
.Fn ASN1_OCTET_STRING_cmp ,
.Fn ASN1_STRING_data ,
.Fn ASN1_OCTET_STRING_dup ,
and
.Fn ASN1_STRING_type
first appeared in SSLeay 0.8.0.
.Fn ASN1_STRING_length
first appeared in SSLeay 0.9.0.
All these functions have been available since
.Ox 2.4 .
.Pp
.Fn ASN1_STRING_length_set
first appeared in OpenSSL 0.9.5 and has been available since
.Ox 2.7 .
.Pp
.Fn ASN1_STRING_to_UTF8
first appeared in OpenSSL 0.9.6 and has been available since
.Ox 2.9 .
.Pp
.Fn ASN1_STRING_get0_data
first appeared in OpenSSL 1.1.0 and has been available since
.Ox 6.3 .
